When constructing a deck, decking planks are used to provide the flooring for the deck. These decking planks are conventionally supported by underlying joists to which the decking planks are attached. In many cases the decking planks may run in length from 12 to 16 feet and are commonly 2×6 planks. If the decking planks are not exactly straight, it has been a problem to straighten these planks before attaching them to the underlying floor joists. The present invention provides a tool for straightening these wooden planks when installing decking planks on floor joists.